If I want to buy a $500,000 and can get a 30-year mortgage with an APR = 3.5%, what would my monthly payments be? If I can get a 15 year mortgage for 2.5%, how much would I save? I've checked with my bank and I can spend $450 a month on a car. If they offer a 5-year loan with an APR = 2.5%, how much car can I afford? (Hint: I give you R, you need to solve for P.)